Thin, mounted, sensitized emulsion



Patented Feb. 5, 192.

ihtthtilil ATENT! @FFHQEO ROBERT J OHN, OF NEW YORK, N. Y., ASSIGNOR T0 DAYLIGHT FILM CORPORATION, A CORPORATION OF NEW ,XORK.

THIN, MOUNTED, SENSITIZED EMULSION.

No Drawing.

To all whom it may concern:

Be it known that I, Bonner JOHN, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new anduseful Thin, Mounted, Sensitized Emulsion, of which the following is a specification.

My invention relates to a thin, mounted, sensitized emulsion and process of making a contact transfer printing surface and has for its object to produce a printing surface which is mounted on a suitable carrier and which represents photographic lights and shades in such a manner that copies may be made therefrom by a dye or ink transfer contact process.

F or purposes of illustration, my invention will be described in connection with the formation of a printing surface obtained by exposing to the action of light modified by the lights'and shades of a completed negative which it is desired to reproduce, a sensitized emulsion mounted on a transparent carrier through which it preferably is exposed, which then is treated to form a hardened printing surface. If it is desired that the printing surface consist of granules or great numbers of photographically formed, extremely minute, individual protuberances which are distributed and grouped irregularly so as to represent photographic lights and shades, it may be obtained, for example,

by treating the emulsion in the manner setforth in my Patent No. 1,374,853 issued April 12, 1921.

It is considered desirable in producing a printing surface to expose the sensitized emulsion through its transparent carrier rather than on its outside surface in order that the printing surface may be as close as.possible to the carrier. is exposed on its outside surface, it is necessary to strip the emulsion from itscarrier 1n order to remove the unhardened portions which will lie adjacent the carrier. Stripping the emulsion is a delicate operation which can be erformed only by those skilled in the art and is likely to injure the image.

When an emulsion is exposed throughits transparent carrier, however, certain difiiculties are encountered in the formation of the printin surface. In the first place, the treating so ution must penetrate the entire emulsion in order to reach the light affected portions adjacent the transparent carrier.

If, the emulsion Application filed July 25, 1919. Serial No. 313,239.

, excess of alkali has a tendency to affect the image unfavorably, destroy the delicate intermediate shades, and make it too contrasting. In the second place, an ordinary sensitized emulsion usually is in excess of onethousandth of an inch in thickness, while the preferable printing surface adjacent the carrier should be very thin, substantially one ten-thousandth of an inch or less. As this thick emulsion will be penetrated deeply by the light to which it is exposed, particularly that portion of the light coming through clear spaces or light shadows in the negative which is being reproduced, the resultant printing surface after treatment will give a relatively too thick printing surface in those portions. flhis undesirable thickness is increased by the use of an alkali as referred to above. It is very dificult, therefore, to get the darker portions of the negative recorded properly without having the lighter portions of the negative registered too heavy and deep. 7

. One manner of overcoming the above difliculties has been to incorporate in the emulsion a. light-restraining agent such as tar trazine or a chrome yellow pigment which has the property of absorbing or slowing down the action of the printing rays Suficiently to enable the dark portions of the negative which is being reproduced to be registered on the sensitized particles in the emulsion adjacent the carrier, before the printing rays coming through light portions of the negative have penetrated the emulsion so deeply as to form a printing surface which is too thick in the portions corresponding to said light portions of the negative, after. the printing surface has been treated and the portions of emulsion unaffected by light removed. The use of these 1i ht-restraining agents, however, has disadvantages, among which may be mentioned their deterring effect on the sensitized emulsion so that a longer time of exposure is required. Although this additional time of exposure is not a serious handicap in plate photography ture photogrhphy where the speed of runit is important in motion picning the large number of individual pic- 1110 111 iasaeii tures upon a motion picture film through the printer is a material factor.

In order to overcome these disadvantages, I have discovered that excellent results may be obtained by the use of an emulsion much thinner than any heretofore used. Instead proximately only one ten-thousandth of an inch from the inner surface of the carrier, s that when the printing surface is obtained after treatment a perfect reproduction of the negative in reverse has been formed, all of which is so close to the inner surface of the carrier as not to have the too contrasting or paddy effect resulting from a printing surface having portions of comparatively excessive thickness.

Many modifications of my invention will be apparent to those skilled in the art without departing therefrom orfrom the scope of the invention, my invention not being limited to any particular emulsion or carrier but comprising a carrier having a sensitized emulsion thereon of such thickness that when exposed to the action of light modified by desired fights and shades it will register said lights and shades in the emulsion with all the gradations from light to dark without a too great contrasting effect.

What I claim is:

1. A carrier having a sensitized emulsion thereon which is so thin that when exposed to light of greatly varying photographic intensity, the portions of emulsion affected by the deepest light penetration will not lie so far from the portions affected by the shallowest light penetration, as to cause perceptible contrasting effects between said portions.

2. A carrier having a sensitized emulsion mounted thereon of approximately only one ten-thousandth of an inch in thickness.

3. A transparent carrier having a sensitized emulsion thereon which is so thin that when exposed through its transparent carrier to light of greatly varying photographic intensity, the portions of emulsion affected by the deepest light penetration will not lie so far from the portions affected by the shallowest light penetration and lying closely adjacent the carrier, as to cause perceptible contrasting effects between said portions.

4. A transparent carrier having a sensitized emulsion mounted thereon of approximately only one ten-thousandth of an inch in thickness.

In testimony that I claim the foregoing, I have hereunto set my hand this 23rd day of July, 1919.

ROBERT JOHN. 

